The Roman Empire.
Washington, D.C. :  National Geographic Society, 
1997.
Contents: 1: 49 B.C. - A.D. 14. Consolidation of the Empire -- 2: A.D. 69-138. Height of the Empire -- 3: A.D. 235-284. The Empire in crisis -- 4: A.D. 284-337. Division of power and Empire.